Re: [PATCH-for-6.1?] target/mips: Remove MOVZ/MOVN opcodes from Loongson 2E

[Philippe Mathieu-Daudé]

On 7/31/21 4:41 PM, Philippe Mathieu-Daudé wrote:
> Per the "Godson-2E User Manual v0.6", the Loongson 2E processor
> does not implement the MOVZ/MOVN instructions

I'm confused because I can't find MOVZ/MOVN in the 2E manual and
the 2F explicits the difference. However looking at binutils,
these opcodes are also emited on the 2E:
https://sourceware.org/git/?p=binutils-gdb.git;a=commitdiff;h=350cc38db21f1cd651a6d46687542a0fce5e0303;hp=569502941afa825c5278b320ccedeefc82e8ed0e

Cc'ing Mark & Maciej in case they can enlighten me, and few
Loongson develeper in case they could check, because I don't
have 2E hardware to test.

> However it's enhanced version, the STLS2F01 processor, does.
> See STLS2F01 User Manual (rev 1), chapter 13.1 "The compliance
> overview":
> 
>   The STLS2F01 processor implements several special MIPS IV
>   instructions as the supplement to the MIPS III instructions.
>   These instructions include two MIPS IV instructions (i.e. MOVZ
>   and MOVNZ) ...
> 
> Fixes: aa8f40090ab ("target-mips: enable movn/movz on loongson 2E & 2F")
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  target/mips/tcg/translate.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/target/mips/tcg/translate.c b/target/mips/tcg/translate.c
> index bf71724f3f0..34a96159d15 100644
> --- a/target/mips/tcg/translate.c
> +++ b/target/mips/tcg/translate.c
> @@ -14156,8 +14156,7 @@ static void decode_opc_special_legacy(CPUMIPSState 
> *env, DisasContext *ctx)
>      switch (op1) {
>      case OPC_MOVN:         /* Conditional move */
>      case OPC_MOVZ:
> -        check_insn(ctx, ISA_MIPS4 | ISA_MIPS_R1 |
> -                   INSN_LOONGSON2E | INSN_LOONGSON2F);
> +        check_insn(ctx, ISA_MIPS4 | ISA_MIPS_R1 | INSN_LOONGSON2F);
>          gen_cond_move(ctx, op1, rd, rs, rt);
>          break;
>      case OPC_MFHI:          /* Move from HI/LO */
>